Question 953993: Express commuter train #12 leaves the downtown station and travels at an average speed of 50miles per hour towards the north side station, which is 60miles away. Fifteen minutes later, express commuter train #7 leaves the north side station and travels at an average speed of 45miles per hour towards the downtown station.
At the moment when the two trains pass each other, how far (in miles) is the #12 train from the downtown station and how long (in minutes) has the #12 train have been traveling?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Express commuter train #12 leaves the downtown station and travels at an average speed of 50miles per hour towards the north side station, which is 60 miles away.
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Fifteen minutes later, express commuter train #7 leaves the north side station and travels at an average speed of 45miles per hour towards the downtown station.
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At the moment when the two trains pass each other, how far (in miles) is the #12 train from the downtown station and how long (in minutes) has the #12 train have been traveling?
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let t = travel time of #7 (in hrs, because we are dealing in mph))
then
(t+.25) = travel time of #12 (in hrs, left 15 min earlier)
:)
When the two trains meet, their total travel distances add up to 60 miles.
Write a distance equation, dist = speed * time
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#12 dist + #7 dist = 60 mi
50(t+.25) + 45t = 60
50t + 12.5 + 45t = 60
95t = 60 - 12.5
95t = 47.5
t = 47.5/95
t = .5 hrs, travel time of #7
then
.5 + .25 = .75 hrs is the travel time of #12
Find how far #12 has traveled in this time
.75*50 = 37.5 mi from the the downtown station
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"and how long (in minutes) has the #12 train have been traveling?"
convert to min: .75(60) = 45 min
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;
Confirm this solution by finding the distance traveled by #7
.5*45 = 22.5 mi
Total distance should add up to 60
22.5 + 37.5 = 60 mi
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I have to commend you.
The problem is written with Capital letters, punctuation, and correct spelling.
Unfortunately, you are the exception, not the rule around here.
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